Simulate/Force Analog Inputs with Emerson RX3i PACSystems?

[Stomachbuzz]

Hi there,

I'm doing some extensive testing and commissioning with a slew of new Emerson PACSystems RX3i PLCs. It would be convenient to simulate/force an analog input reading. It seems I can Force DIs, DOs, and AOs, but cannot find a way to force AIs. Is this correct?

Thanks

EDIT: Using PAC ME. When right clicking on a field in the %AI memory table, there is an available option for "Write" and lets me type a number in, but does not accept it.

 

[Steve Bailey]

You are correct. You can't force analog inputs. One thing you could do, since you are commissioning, is to change the hardware configuration and assign a different %AI address to the analog input module. Then you could write any value you want to the original %AI address in logic. Just don't forget to restore the correct address when your testing is complete.

 

[Stomachbuzz]

You are correct. You can't force analog inputs. One thing you could do, since you are commissioning, is to change the hardware configuration and assign a different %AI address to the analog input module. Then you could write any value you want to the original %AI address in logic. Just don't forget to restore the correct address when your testing is complete.

Ah gotcha.
Thanks for confirming that!
I appreciate the tip. That's pretty clever. I've done similar stuff with Building Automation controllers.
What you're essentially saying is to remap the pointers/references for the AIs to an area of memory I can freely edit?

Let me ask you this, then: what is the best way to view memory contents? Such as seeing a map/profile of what areas of memory are free or used? I know there is a Report generator function, but that left some things to be desired from what I remember.

 

[Steve Bailey]

What you're essentially saying is to remap the pointers/references for the AIs to an area of memory I can freely edit?

I wouldn't describe it quite that way. I'm suggesting to remap the AI module to some unused address, leaving the ladder logic alone. If you do that, when the PLC refreshes the data from the module, it won't overwrite the value you're using for your test.

 

[Stomachbuzz]

I wouldn't describe it quite that way. I'm suggesting to remap the AI module to some unused address, leaving the ladder logic alone. If you do that, when the PLC refreshes the data from the module, it won't overwrite the value you're using for your test.

Yes, I understand now. I misinterpreted what you said in my last post.

I understood you properly, which prompted me to edit my post asking how to properly view memory usage - I.E. find an appropriate memory address to assign the AI module.

 

[Steve Bailey]

The easiest way to find an unused analog input address is to simply enter "%AI" without specifying the address. The software keeps track of the highest address used and will select the next available. It doesn't try to fill in gaps.